Laundry drier and combination thereof with domestic furnace



May 11, 1954 G. B. HERBSTER 2,677,397

LAUNDRY DRIER AND COMBINATION THEREOF WITH DOMESTIC FURNACE s Sheets-Sheet 1 Filed Oct. 26, 1949 We w. M m T. W I m m L {I w r M 4. H 0 6 4 m\ I fow M m v. f 4 m m a \l h n u hhwll I l1. 2 s 5 TH I I III 5 m l j Z x z h ,9 /FI||.\\\\ f wlllllllllllllll, T x win 6 W' 0 l m 5 h l H W m IIIIII I" u u G. B. HERBSTER 2,677,897 LAUNDRY DRIER AND COMBINATION THEREOF WITH DOMESTIC FURNACE May 11, 1954 6 Sheets-Sheet 2 Filed Oct. 26, 1949 JNVENTOR.

MUM w W a HTTOHNEVS;

Hull

May 11, 1954 G. B. HERBSTER 2,677,897 LAUNDRY DRIER AND COMBINATION THEREOF WITH DOMESTIC FURNACE Filed Oct. 26. 1949 6 Sheets-Sheet 3 "m, X? 11W;

Hum!

z 36' j a; I H 4 j 3 1 I 24 Z 7 1/ i 24; 33 I 4/ l ili i::: I

1' I 'ff JJ INVENTOR.

66 BYM ML; 40

' Mf'M rsZ, fig 5 HTTbR/VE v5.

STER

G. B. HERB 2,677,897 LAUNDRY DRIER AND COMBINATION THEREOF WITH DOMESTIC FURNACE May 11, 1954 Filed Oct. 26, 1949 6 Sheets-Sheet 4 5 a 2 u l 7 .1 M TH I? "IT? 7 pH+N1 H T 6 M G H m n; w I F 4, 4 1/ 6 6 6 6 INVENTOR. W, BY

A 770R/VEY5 G. B. HERBSTER RY DRIE THEREOF WIT May 11, 1954 LAUND R AND COMBINATION F l d. 0 t 26 194 H DOMESTIC FURNACE l e C v 6 Sheets-Sheet 5 5 N R m. m N 16 in @WM 14 w I\.%@

y 1954 G. B. HERBSTER 2,677,897

LAUNDRY DRIER AND COMBINATION THEREOF WITH DOMESTIC FURNACE Filed Oct. 26, 1949 6 SheetsSheat 6 INVENTOR. iq- 15 21 6. 14 421,,

Patented May 11, 1954 LAUNDRY DRIER AND COMBINATION THEREOF WITH DOMESTIC FURNACE George B. Herbster, Cleveland, Ohio, assignor, by

mesne assignments, to Cleveland, Ohio, a cor 8600 Denison Company, poration of Ohio Application October 26, 1949, Serial No. 123,623

6 Claims.

This invention relates to a new and improved laundry drier of the rotary drum type and to a combination thereof with a domestic furnace of the centralized forced air circulating type.

The drier itself is such that a very rapidly moving large volume forced stream of dry, moderately heated air is maintained through an enclosed rotary drum, the air inlet to which is arranged to introduce the air into the drum so as to cause the air to flow initially in a direction generally upwardly inwardly to the central portion of the drum across the lower portion of the path of falling pieces of laundry being tumbled and dried therein, and the exhaust to which is arranged to cause the air to flow generally upwardly and outwardly from the central portion of the drum across the upper portion of the path of the falling pieces of laundry and immediately out of the drum, with the combined result that the pieces are loosened and spread, both mechanically and by means of the air stream, exposing large areas thereof to a large volume of continuously replaced moderately heated fresh air and the freed moisture is conveyed away instantly whereby the pieces are dried thoroughly and rapidly.

Another feature of the present invention resides in the combination with a centralized forced air household heating furnace capable of heating the entire house by distribution of heated air through the usual household distribution duct system, of a rotary drier so arranged and related to the furnace that all, or substantially all, of the air delivered by the furnace can be by-passed through the drier into intimate contact with the pieces of laundry therein and discharged promptly into the atmosphere outside of the house, wherey the drying operation is effected by means of a large volume of rapidly moving dry air in moderately heated condition in a small fraction of the time heretofore required, the high temperature heating sources or elements in the drier or in close proximity to the pieces to be dried are not required, the subjection of the pieces being dried to concentrated radiated heat or to relatively high temperature air is eliminated, and the pieces when dried are soft and fiuffy.

The rapidity of drying of the clothes or other pieces of laundry at low temperature is further increased by the application of the heated air in a manner to assist in agitation of the pieces and by the immediate withdrawal of the moisture laden air.

More specifically, in the present drier, the drum has a foraminous circumferential wall and is so arranged and confined that the stream of air is constrained to enter the drum through the circumferential wall thereof in that lower quadrant in which the circumferential wall of the drum is travelling downwardly and constrained to pass out of the drum through the circumferential wall thereof in that upper quadrant in which the circumferential wall of the drum is travelling downwardly, whereby the air is applied to the pieces of laundry while they are spaced from any wall surface against which they could pack under the force of the air stream and whereby their fall is slightly delayed and they are spread, agitated and tumbled about by the air stream so as to afford an opportunity for the air to pass readily into contact with all surfaces of the pieces and promptly out of contact therewith and immediately out of the drum.

An object of the invention is to provide a rotary drum, hot air drier capable of drying pieces of laundry which leaves them in a soft and fluffy condition at the completion of the drying operation.

Other objects and advantages will become apparent from the following description wherein reference is made to the drawings, in which:

Fig. 1 is a right side elevation of a furnace and drier combination embodying the principles of the present invention, part of the casing thereof being broken away for clearness in illustration;

Fig. 2 is a left side elevation of the apparatus illustrated in Fig. 1, part thereof being broken away for clearness in illustration;

Fig. 3 is an enlarged fragmentary vertical sectional view taken on the line 33 in Fig. 2;

Fig. 4 is a top plan view of the apparatus, part thereof being shown in section and part broken away to illustrate more clearly the drier drum and by-pass damper;

Fig. 5 is a fragmentary vertical sectional view of the drier and valve chamber therefor, and is shown in elevation;

Figs. 6 and '7 are fragmentary sectional views taken on lines 6-45 and l-!, respectively, of Fig. 5, and illustrating the by-pass and control damper;

Fig. 8 is a vertical sectional view of the furnace of the combination and is taken on planes extending generally forwardly and rearwardly, as indicated by line 8-8 of Fig. 9, part thereof being shown in elevation for clearness in illustration;

Fig. 9 is a vertical sectional view taken on line 9--9 of Fig. 8, part thereof being shown in elevation; and

Figs. 10, 1i, and 12 are various wiring diagrams illustrating control systems for controlling the operation of the drier and furnace combination of the present invention.

The drier of the present invention comprises essentially a rotary cylindrical tumbling drum I which has a foraminous or open wire mesh circumferential wall so as to permit the free ingress and egress of air therethrough. The drum preferably has a solid end wall 2 at one end by which it is supported for rotation with its axis horizontal.

A plurality of paddles or agitators 3 are arranged on the inner surface of the circumferential wall of the drum and extend longitudinally of the drum. The paddles 3 likewise preferably are of foraminous structure so that air can readily flow through the paddles as well as the circumferential wall.

The drum I is enclosed in a suitable casing 4 of which the walls, except as hereinafter pointed out, closely confine the drum with slight operating clearance. The other end wall 5 of the drum has a large central opening therein for charging and discharging laundry pieces to be dried.

A charging opening is provided in the corresponding side wall of the casing 4 in alignment with the opening in the drum wall 5, a suitable door 6 being provided for closing the opening in the casing wall during the drying operation.

The drum is supported in the casing for rotation about a horizontal axis by a shaft 1 which is fixedly connected to the end wall 2 of the drum. The shaft 1 is rotatably supported in a suitable bearing 8 which extends through the side wall of the casing 4 and is mounted on a bracket 9.

For driving the drum I is a pulley it is fix edly mounted on the shaft I and is driven through a suitable belt by a reduction pulley H. The pulley I I is rotatably mounted on a suitable shaft I2 which is carried by a vertical slide it so that the shaft I2 may be adjusted vertically transversely of the shaft axis. The slide I3 is carried in a guide bracket I4 secured to the casing wall. Mounted on the shaft I2 for rotation with the pulley II is a pulley I5 which, in turn, is drivingly connected by a belt IE to a motor I'l. A tension spring I8, connected at its ends to the slide I3 and bracket I4, respectively, normally urges the bearing I3 toward the axis of the drier. The motor I1 is carried on a hinged plate for adjustment vertically by means of a suitable screw I9. Thus the drum is driven at reduced speed and the driving belts are maintained at the proper tension by vertical adjustment of the motor.

A cover is providedon the casing 4 at the supported end of the drum I so as to house the pulleys and bearings and to segregate them from the drum compartment formed by the casing 4.

The motor I'I is arranged to drive the drum counterclockwise, as viewed in Fig. 1 and Fig. 5, so that when the clothes or pieces of laundry carried in the drum are lifted by the paddles 3, they drop downwardly from the circumferential wall of the drum through the upper left hand quadrant of the drum and fall onto the circumferential wall of the bottom of the lower left hand quadrant or onto the bottom of the drum just beyond the lower lefthand quadrant in the direction of travel of the circumferential wall.

It is necessary to apply a large volume of dry, moderately heated air to the pieces being dried from the vertical fully in a manner such that the air spreads them and assists in agitating them. Accordingly, referring to Fig. 5, the air is caused to enter the drum through its circumferential wall and pass upwardly and inwardly of the drum through its lower left hand quadrant across the path of the falling pieces. For this purpose the casing 4 is provided with an inlet opening 2| so arranged that the air from a suitable source, such as a forced air circulation furnace, later to be described, enters the casing 4 somewhat upwardly and inwardly and directly onto the circumferential wall of the drum I in that one of the lower quadrants of the drum in which the circumferential wall is travelling downwardly. In the form illustrated the casing 4 is shown as having its wall in which the inlet passage 2I is located juxtaposed against one wall of a valve chamber 22 which is connected between the plenum chamber of the furnace and an outlet or household distribution duct of the furnace.

The juxtaposed wall of the valve chamber has a passage 23 aligned with the passage 2I and forming a continuation thereof. The passages 2I and 23 are controlled by a suiatble damper 24 which is hinged at its upper edge to the wall of the valve chamber adjacent the top of the opening 23. The damper 24 is operated by a handle 25 through the medium of a shaft 26 and linkage 21. The damper 24 preferably occupies a vertical position when in the closing relation to the passages 23 and 2| so that all of the air entering the valve chamber 22 continues upwardly into and through a household distribution duct 28 of the furnace into the rooms to be heated. A disc 29 is fixedly secured to and carries a detent 3B which can be engaged selectively with suitable spaced holes in the side wall (H of the valve chamber 22, as best illustrated in Fig. 7. For this purpose the shaft 28 is arranged to be shiftable axially and is urged endwise for engaging the detent with the selected one of the holes by means of a spring 32. Thus the handle 25 may be operated to swing the damper 24 closed position in which it closes the passages 2i and 23 to a fully open position, as illustrated in Fig. 5, in whichlatter position it slopes downwardly away from the top of the opening 23 at about 45 to the horizontal and blocks the passage of air from the valve chamber 22 into the duct 28 and admits all of the air from the furnace through the passages 2| and 23 into the casing 4 of the drier. In this open position, it acts to direct the air, as indicated by the lower ones of the arrows 33 in Fig. 5, upwardly and inwardly of thedrum through the circumferential wall thereof at thatone of the lower quadrants in which the circumferential wall of the drum is travelling downwardlly. The damper preferably is kept fully open when the drier is being used. However, by means of the'detent 30, the damper 24 may be adjusted manually to pass part of the air from the furnace to the rooms of the house and part only through the drier concurrently.

In order to assure a rapid flow of the air andv its effective application to the pieces of laundry, the air is permitted to exhaust from the drum I and from the casing 4 at that one of the upper quadrants of the drum in which the circumferential wall of the drum is travelling downwardly, this being the upper left hand quadrant in Fig. 5.

An upper portion of the forward wall of the casing ,4 and forward portion of the top wall of the casing 4 are spaced wardly respectively from the circumferential quadrant into which the air is admitted. The spaced portions are substantially coextensive with the drum lengthwise of the drum and of a circumferential extent substantially equal to said left hand the air exhausts freely through the circumfer- This assures its passage across the path of the downwardly falling loose pieces of laundry.

The top wall of the casing 4, at the spaced portion above described, is provided with a large exhaust opening or passage 34 which is of adequate size to permit free passage out of the casing 4 of the air delivery of the blower, allowance being made for the increase in the volume of the delivered air resulting from absorption of moisture in the drier, connects with a suitable exhaust duct 35. The duct 35, in turn, is connected to an outlet duct 36 which leads to the usual stack even after the filter tial deposit of lint.

The peripheral wall of the casing 4 is thermally insulated, as indicated at 39, by suitable material not only to conserve heat for drying but also, and primarily, to prevent undue heating of the room in which the drier is located.

The walls of the casing 4 alongside the ends of the drum are closely adjacent to the ends of the drum l and the casing walls adjacent the circumferential wall of the drum are located very close to the circumferential wall of the drum in those quadrants in which the circumferential wall is travelling upwardly, these being the right hand quadrants in Fig. 5, and particularly at the bottom of the drum and at a location immediately above the inlet passage 2|. This relation of the drum and casing constrains substantially all of the air entering the passage 2| to pass into and immediately out of the drum through the circumferential wall thereof instead of around the end walls tial wall of the drum. To assist in causing the air to enter the drum at the lower left hand quadrant, as described in connection with Fig. 5, the wall of the casing 4 is preferably spaced a considerable distance from the circumferential wall of the drum at the lower left hand quadrant in Fig. 5 as well as immediately above that point of closest approach of the circumferential wall of the drum to the wall of the casing which is just above the inlet opening 2|. Sufficient air can pass around the ends and circumferential wall of the drum, however, to carry away lint, dust and the like which would otherwise tend to accumulate in the casing.

Referring next particularly to Figs. 1, 8 and 9, the furnace shown in connection with the drier is preferably such as described in detail accumulating chamber,

6 in my copending application filed November 21, 1947, now

Serial No. 787,455, Patent No. 2,564,- the form illustrated it is surmounted by with the central passage and open at their outer ends for discharge of the air radially from between the heads. Each of the heads is corrugated with circumferentially extending corrugations spaced apart radially of the head so as to divide the head, in effect, into a plurality of concentric tubes. Each of the heads is provided at its bottom with a combustion chamber portion 43 connected with the tubes thus formed and at its top with an exhaust portion 44 connected with the tubes so that combustible media and combustion products can pass from the combustion chamber portions 43 through the heads 4! and out through the exhaust portions 44 to a common exhaust flue 45 which leads to a suitable outlet flue .5, later to be described.

A gas burner t? is provided for supplying heating media into 4-3. It is enclosed in a suitable compartment 48 grilled door 55. The opening 49 also affords access to the interior of the burner compartment.

pulley 52, 53, and electric motor 54. Surrounding the row of heat exchange heads 4| is a housing 55 having a spirally expanding cirwall and radially extending side The side walls are provided with suitable passages 55 which are coaxial with the impeller 5| and admit air to be heated and circulated to the interior of the impeller. The housing 55 at with an extension to the circumferential wall and which provides a plenum or air indicated at 51, which the heated air from the radial passages between the heads is discharged.

The plenum chamber 57 is connected with the valve chamber 22 of the drier so as to discharge thereinto. The entire furnace, including the housing 55 and plenum chamber 57 is enclosed in a suitable casing 58, the walls of which are in of th housing 55 and into the openings 55. The air to be heated is admitted into the casing 58 through a suitable passage 59 in which is mounted an air filter 55.

The flue 46 is connected to the stack 31, heretofore described, by being extended upwardly thereinto across the interior of the duct 36. The

er-enact. the flue 46 is positioned a shortdis usual-volume for discharging through the usual.

distribution duct system into the rooms of the house for heating the house. Thus a large volume of dry air at relatively moderate temperature compared to that of prior driers is supplied and may be utilized in whole or part for the heating of the house or for drying pieces of laundry-or clothes.

Theapparatus may be operated manually by suitable manual electric switches and by setting of ;the. handle 25 and adjusting the damper 24 in accordance with the heating requirements of the :house and the requirements of the drier. However, it is preferable that the apparatus be operated semi-automatically, as will later be explained; and when this is done suitable by-pass openings 6| are provided in the side wall 3| of the valve chamber 22. The openings 6| are controlled by a rotatable damper 62 which is operated'by a solenoid plunger 63 and is arranged, when opened, to by-pass a limited volume of air from the valve chamber 22 around the damper 24 into the duct 28, as best illustrated in Fig. 6 by the arrows 64. This by-pass is provided in those instances in which the device is to be operated to admit additional heated air to the rooms when called for'by a room thermostat when the damper 24 is fully open, as illustrated in Fig. 5-, or'is open to such an extent from the inlet openings 2| and 23 that an inadequate amount of air can pass around the free edge thereof into the duct 28. I

For semi-automatic operation, the wiring diagram illustrated in Fig. is satisfactory.

Referring to the wiring diagram shown in Fig. |0,--the blower motor 54 is connected across the usual 110 volt A. C. source in series with a normally open adjustable thermostatic switch 65 arranged to be heated directly by the heating heads 4| so that the blower motor is turned on only when the temperature of the heating heads 4| of thefurnacehave reached a proper degree to adequately heat the air which will be blown through the furnace by the blower. Thus the blower motor is dependent for its operation entirely upon the preselected temperature of the heating heads of the furnace. The motor l1 which drives the tumbling drum of the drier is connected across the 110 volt circuit in series with a normally closed switch 66. The switch 66 is so arranged as to be held open when the damper 24 is closed and to close when the damper 24 is opened beyond a predetermined amount for admitting air from the valve chamber 22 into the drier through the openings 2| and 23 and to remain closed from this position to more widely open and fully open positions of the damper 24. Since the furnace is used primarily for heating the house, the damper 24 is normally kept closed thus holding the switch 66 open. Only when the damper 24 is open to admit air to the drier is the drum rotated.

In order to control the temperature of the furnace and drier and to provide adequate safety, a lower voltage control circuit is employed. A transformer 61 is connected with its primary across the 110 volt circuit and its secondary across 8 th'control circuit. "A safety pilot 68 in the form of a thermocouple which generates its own cur-" rent is provided for opening and closing a switch 69 in the control circuit. The switch 69 is-normally open and is closed only when the thermostat is being heated by the flame of a pilot burner 10 of the furnace. in the control circuit in series with a normally closed high limit thermostatic switch 1| which is responsive to the heat of the heating heads 4| of the furnace so as to break the circuit and pre-' vent overheating of the heads should the other safety controls fail. Connected in series with the high limit control switch 1| is a room thermo static switch 12 which is normally open and closes when heat is required in the rooms of thehouse. A solenoid valve 13 for admitting gas to the main burner of the furnace is connected in the control circuit in the series with the room thermostat.

Thus the pilot operated safety switch 69, the high- 1|, the room thermolimit thermostatic switch static switch 12, and the solenoid valve 13 for supplying gas to the burner are connected in series with each other. switch 69 is closed, the high limit switch 1| is normally closed, and, if heat is required in the room, the switch 12. is closed, thus opening the solenoid valve 13 and supplying gas to the burner. When the heads 4| reach a sufficiently high temperature, the thermostatic switch 65 closes to cause the blower motor 54 to drive the blower. How ever, it is desirable drier be independent of the room thermostat and dependent instead upon the temperature within the drier casing 2|. For example, in summer, the room thermostat may remain open indefinitely. Accordingly a normally closed thermostatic switch 14 and a normally closed switch 15 are connected in series with each other in a bypass circuit around the room thermostatic switch 12. The switch 15 is arranged so as to be held open by the damper 24 when the damper is in closed position and is permitted to close upon opening of the damper to admit air into the drier inlet opening 2|, and to remain closed during additional opening of the damper 24 to fully open position. When the damper 24'is open a sufficient amount, the heat sup plied by the furnace is controlled by the thermostatic switch 14 which is responsive to the temperature in the casing 4 of the drier and which continues to remain closed and call for heat unti1 a sufficiently high temperature in the casing 4 is obtained.

However, in cold weather, should additional heat be required in the rooms during the operation of the drier such would not be supplied unless the damper 24 were only partly open. In many instances, with the damper 24 about three quarters open and with the admission of about one quarter of the air into the rooms, the rooms of the house can be maintained at the proper temperature independently of the room thermostat 12, such room temperature being slightly below that which would normally be desired, but this increases the drying time required. Since the drier is used only for a short interval of time, usually it is preferably to maintain the damper 24 fully open to the drier so that no heat is supplied to the rooms, inasmuch as the rooms tend to maintain their temperature for an appreciable time except in severe weather. However, due to the human element, it is desirable in severe weather that the by-pass 5| be used and the apparatus be madefully automatic to supply all of the air from The switch 69 is connected With the pilot operating, the

that the supply of heat to the I 24 a predetermined degree the furnace to the drier until some heat is called for by the room thermostats, and then to supply only enough to the rooms so as not to interfere with the drier to any greater degree than necessary.

Figs. 11 and 12 are wiring diagram showing modifications, respectively, of the wiring diagram illustrated in fig. for use in those instances in which the normally closed by-pass damper i l is to be used and opened in response to the requirement of heat by the room thermostat. For brevity in description, in Fig. 11 the parts heretofore described are indicated by the same numerals as heretofore applied but followed by the sufiix a and the same is true in Fig. 11 except that the numerals are followed by the suiiiX b.

Referring in detail to Fig. 11, the by-pass damper, indicated at 62a, is operated by the solenoid 63a. The other elements are connected in the same manner as des :ribed in connection with Fig. 10 except that between the room thermostat 72a and the solenoid valve 13a there is provided a normally closed switch 16.

and the solenoid valve 13a, a switch 7'! being connected in series with the solenoid 63a in the parallel circuit. A suitable switch operating solenoid i8 is connected in parallel with the drier motor Ila and is arranged to operate the switches 75a, 76 and 1'! simultaneously, concurrently closing 15a and l! and opening it when energized and restoring them to the position shown, when deenergized. Thus, when the furnace or heater is being operated to heat the house, the circuit 53a and the drier temperature thermostat 74a being disconnected.

Upon opening the main damper 24 for admitting the air from the valve chamber 22 into the casing it of the drier, the switch 60a is closed which starts the drier motor Il a, at the same time energizing the solenoid 18 which operates to open switch it and close switches 75a and H. Thus the operation of the solenoid valve 13a, which was interrupted by opening of the switch it, is maintained through the switch 75a and at the same time the damper solenoid 63a is connected by the switch ill in series with the room thermostat so as to be operative in response thereto. However, the solenoid 73a is no longer under the control of the room thermostat but under the control of the drier thermostatic switch l la. Accordingly, therefore, the only effect of operation of the room thermostat is to cause the solenoid 53a to open and close the damper 6.2a. Since threeswitch relays are readily available on the market, such may be used for this purpose, the common relay coil being the coil ill and the three switches of the relay being 15a, 76 and Ti.

Instead of the relay, four separate switches may be used and are connected together mechanically for concurrent operation. Such an arrangement is illustrated in Fig. 12 in which the switch 65b which controls the drier motor llb is connected to switches 55b, 'i'tb and ill) which correspond to the switches its, 56 and i! described in connection with Fig. 11. These switches are so arranged that upon opening the damper 2 3 for admitting heat to the drier, the switch 552) is closed, thus starting the drier motor Ila. Concurrently, the switch 56b is opened and I'll; closed so as to place the solenoid valve 73?) under the control of the drier thermostatic 5 switch 141). At the same time the switch 11b is closed, thus placing the damper 62b under the control of the room thermostat.

Since the furnace illustrated is one of very high efficiency relative to its size it i believed that a better understanding of the ratio of the volume of heated air supplied to the volumetric capacity of the drier will be of assistance in understanding the invention.

In the form illustrated, the furnace has a capacity of about 80,000 B. t. u. output, adequate for heating a rather large house. When used for drying, the furnace operates intermittently, having a total on time equal to about half of the dryin period, thus supplying about 40,000 B. t. us. The blower operates continuously and delivers 900 cubic feet of air per minute to the drier, delivering the air at a temperature of about to degrees Fahrenheit. All of this air is drum is about 27 charge of wet wash comprised of the lighter pieces, such as shirts, pillow slips, house dresses and the like, which charge, after having passed through the usual roll type domestic wringer weighs about eighteen pounds,

drying a mixed charge of light and heavy materials such a occurs in the average household wash. such an average mixed charge can be accommodated in amounts of twenty-four pounds and dried in about twenty-five minutes.

The charge is not merely damp dried to a condition suitable for ironing but is thoroughly dried.

If, instead of the conventional roll type domestic wringer, a spinner is used, the time required for drying the terially.

equal to the weight of the the spinner drier reduces this ratio materially, and accordingly there is much less water to evaporate. The time element does not appear to depend on the size of the charge. if the charge is kept below the maximum permitted, a full charge drying in about the same time as required if the charge comprises only a few pieces. Greatest overall efiiciency, therefore, is obtained by balancing the charges so that they are as near to maximum capacity of the drum as practical.

Having thus described my invention, I claim: 1. In a household furnace and laundry drier combination, said furnace including a heat exchanger, blower means for blowing outside air into heat exchange relation thereto, a furnace casing enclosing the heat exchanger, and conduit means including a valve chamber leading upwardly from the top of the furnace casing for receiving said heated air and for discharging it into a household distribution duct, said valve chamber having a side wall, a drier mounted on top of said furnace casing and including a drier casing having a side wall facing said side wall of said valve chamber, a drum having a foraminous circumferential wall and being mounted in said drier casing for rotation about a horizontal axis, the space within the drum being unobstructed for permitting free fall of laundry pieces from the circumferential wall of the upper half of the drum to the circumferential wall of the lower half of the drum, the drum being positioned so that its circumferential wall faces, and is .adjacent, said side wall of the drier casing, means to rotate the drum in a direction such that the portion of the circumferential wall adjacent said side wall of the casing is traveling downwardly, said drier casing side wall having an inlet passage opening into that lower quadrant of the drier casing in which the circumferential wall of the drum is travelling downwardly, and facing directly toward the circumferential wall of the drum, and said valve chamber side wall having a passage aligned with and connected to said inlet passage, damper means in the valve chamber passage for controlling the passage of air from the valve chamber through said'passages, said drier casing having an outlet passage adjacent to that upper quadrant of the drum 'in which the circumferential wall of the drum is travelling downwardly and. leading to the atmosphere and disassociated'with the inlet of the blower means, and means in the drier casin constraining the major portion of the air entering the inlet passage to enter said 'drum at said lower quadrant.

2. A laundry drier according to claim 1 characterized in that the peripheral wall of the drier casing within the limits of each of said quadrants vide in each of said quadrants a large and relatively free and unobstructed air space extending endwise of the drum between the peripheral wall and circumferential wall, and said spaces is spaced from the circumferential wall to pro- 30 ing to claim 1 characterized in that the inlet passage of the drier casing is substantially coextensive in length with the drum and is coextensive in height with the major portion of the lower half of the drum.

4. The combination according to claim 1 characterized in that said outlet passage of the drier casing is in that upper quadrant in which the circumferential wall is travelling downwardly. 5. The combination according to claim 4 characterized that in said upper quadrant the periperal wall of the upper casing is spaced from the circumferential wall of the drum to provide a large and relatively free and unobstructed air space extending endwise of the drum between the peripheral wall and the circumferential wall, and the outlet passage is in communication with'said space. 6,,A laundry drier'according to claim 1 characterized in that the bottom of the inlet passage of the drier casing is near the level of the bottom of the drum and the top of the inlet, passage ,of the drier casing is above the levelof the major portion of the circumferential wall insaid lower quadrant.

References Cited in the file of this patent UNITED STATES PATENTS Number 

